The present invention is directed to an oscillator-modulator apparatus and method therefor and more specifically to apparatus for use in video games for home use.
In view of the requirements of the U.S. Federal Communications Commission (FCC) video games which attach to the antenna input terminal of a television receiver must be shielded to prevent excessive electromagnetic radiation. Such video games produce a radio frequency (R.F.) signal which is modulated by the game information. The R.F. signal may correspond to, for example, channel 3 (60-66 MHz) of the television spectrum.
Where the game information includes an audio component the construction of an oscillator-modulator which is sufficiently linear, yet produces relatively low levels of R.F. radiation, may be costly. This is illustrated by a standard television transmitter which has separate picture and sound modulators and R.F. oscillators until the transmitting antenna and then in some cases even uses separate antennas.
Finally in any consumer item, cost from both a raw material and production standpoint is crucial. This includes consistency of output characteristics in mass production.
One prior design which was used by the assignee of the present application in the video game "HOCKEY PONG" (trademark) consisted of a folded metal box shield containing a printed circuit board. This was found to be inadequate for many of the foregoing reasons.